Waterproof paper and process of producing the same



I UNITED. ATES PATENT oFFIc's.

ALBERT L. CLAPP, OF MARBLEHEAD, MASSACHUSETTS.

warnnrnoor rarer. Ami

life Drawing.

To all whom itmag concern.

Be it known that I, ALBERT L. CLAPP, a citizen of the United States, residing'at Mar blehead, of Massachusetts, have invented new and useful Improvements in WaterproofPaper and Processes of Producing the Same, of which the following isa specification. V

This invention relates to the production of Waterproof paper in which the waterproofing compound is added to the stock in the beater.

Heretofore it has beenproposed to render paper waterproof by the precipitation of aluminum soap during the beating operation so as to secure an approximately 'homogeneous mass, but logical disadvantages, because the resultant pulp is sticky and adhesive, and conseusual precipitation of aluminum resinate in waterproof, that the resultin quently the Web-forming machinery soon becomes gummed' and rendered incapable of use. That is to say, the cylinders, the wires and the felts soon become plugged with the when it is wet. ave discovered that it is possible to stick 1 l produce'a waterproof paper by the precipitation of a calcium soap, such as 'calclum oleate, in thebeater stock, and that indeed this may be accomplished together with the the ordinar operation of rosin-sizing paper, without a'hesiveness or tackiness: in the mass of wet pulp. In fact better results are secured by the precipitation of both the calcium soap and the aluminumresinate in 'the stock than are accomplished by eitherprocess carried on separately. his is doubtless due to the fact that a part of-the calcium oleate tends to precipitate in a more orless granular mass and to float out and not adhere to the fibers. On the other hand, if the rosin-sizing is carried on alone, such enormous proportion. of the aluminum resinate must be-present' to render the paper paper 1's too hard and harsh. Where bot the calcium oleate and aluminum resinate are precipitated in the same stock in the beater,-t 7

aluminum resinate, assists in fixing theoleate upon the fibers becauseof its reater retention of water and itsnatural a hesive-- ness, without making the wet pulp gummy or sticky and, since the sod1um-oleate is soft, the resultingpa or is soft'and pliable aswell as waterproo Forsome purposef,

Specification of Letters Patent.

Application filed July 11,

in the county of Essex and State this has its technor is added 5 fibers.

rnocnss or raonucme THE same.

Patented July 6,1920.

1918. Serial TWO-244,477.

it is desirable also to precipitate silica in the beater-stock to give a crackly paper, and this may be accomplished by the use of sodium silicate. The precipitant for both the aluminum resinate and the silica is preferably alum (aluminum sulfate) which is added in sufiicient excess to bring about both reactions and effectively to neutralize any.

alkali. remaining as the result of the chemical reactions. In the other cases, however, I may omit both the aluminum resin-ate and the silica.

, As an example of one method of'carryin out my process, -I proceed as follows: A first produce a sufiicient quantity of soap, preferably sodium oleate, ,of' which a thin aqueous solution is prepared. In making the soap, to a sufiicient quantity of water, ounds of caustic soda, and the solution is eated to about 180 F.- Then 10 pounds of red oil or elaine is added, the

heating continued, and the mass stirred until saponifioation occurs. The beater engine is charged with 1,000 pounds of sulfate pulp, commonly used i kraft paper, althou'g if desired, other paper. stock may be used, where the strength of the paper is not an. especial consideration. I then add 15 pounds of ordinary slaked lime (calcium hydroxid), and, after sufficient water is added to secure the proper circulationof the stock, the beater is started and continued in operation until the contents are thoroughly mlxed. I now pour in the soap solution in suflicient quantit to add 15 pounds of soap to the mass a ready in the beater.

cipitation of finely divided calcium oleate upon and its thorough admixture with the This takes lace in the course of approximately 15 about 25 poundsof sodium sil1cate, and 6 gallons of rosinesize "(sodium' resmate),

the mass. After these have more or less, to been thoroughly 'mixed into the mass Lthen introduce -7 5 to" 100 pounds of alum (aluminum sulfate), with the consequent preci 1- tation of silica and aluminum resinate. e-

uantityof alum is in excess of that needed orthe precipitation of the silica and the aluminum resinate,'- in 'order to neutral ze any free caustic or any free calc um hythe manufacture. of

.ioc minutes, and then I'add the advantagpi of bein 'tating calcium soap .throughout' the stoc droxid that may result from the various .forming mechanism such as a Fourdrinier or a wet machine, and then dried in any suitable manner.

With stock prepared as herein described,-

it is possible to operate the paper-forming mechanism with as great ease and facility as in the regular process of rosin-sizing.

Of course it will be understood that I do not limit myself to the proportions of the ingredients which I have herein descrlbed, nor to the precipitation of silica in the mass, although I regard the presence of the sillca as desirable for some technological purposes. One of the advantages incident to the process which I have herein descnbed, in which sodium oleate is used as one of the raw materials, is the ossibility of carrylng on the beating while e stock is at ordinary temperatures. 1 may, however, substitute therefor a stearate or palmitate, or alkaline salt of the other fatty acids, in which case the stock must be heated in order to formthe corresponding calcium soap. While this has its disadvantages, because of the necessity of'heating the stock, it sometlmes has the cost of eating a ded, because of the relatively low rice of the other forms of the fatty acids. f course, in saponifyin the fatty acids, I may employ the hydroxid of an of the alkaline earth metals.

hat I claim is'z. 1. A process of paper, which comprises mixing a soluble soap with fibrous paper stock and recipitherefrom. 1n and calcium hydroxid to said stock, and then precipitating aluminum resinate in said stock.

1e soap with fibrous paper stock andprecipitating calcium soap therefrom in and throughout the stock by the addition of calcium hydroxid, and than fixing said precipitate' upon the fibers by the preci itation aluminum resinate 1 throu hout K t 'emass in the presenceof said precipitate.

3. A step 'in the processof producing wate roof paper which comprises mixing a solu 1e soap cheaper, even with producing waterproof by the addition offibrous paper stock, pre

cipitating calcium soap therefrom in and throughout the stock by calcium, hydroxid and forming the mass into a sheet. v

4. A step in the process of producing waterproof paper, which. consists in mixing calcium hydroxid with fibrous paper stock, and mixing a soluble soap therewith and precipitating calcium soap throughout the mass of stock. I

5. A process of producing water roof paper, which comprises mixing ca cium hydroxid with fibrous paper stock, mixing a soluble soap therewith and precipitating calcium soap throughout the mass of stock, then mixing sodium resinate with said mass, and adding and mixing alum into the mass and thereby precipitating aluminum resinate therein.

6. A process .of

paper, which comprises first precipitating calcium soap throughout a mass of paper stock then mixin sodium resinate and sodium silicate witg the mass, and finally simultaneously precipitating aluminum resin-' ate and silicathroughout the mass by the addition of alum.

7. A process of producing waterproof paper, which comprises first precipitating calcium soap throughout a mass of paper stock, then mixing sodium resinate and sodium silicate with the. mass'and finall adding alum in excess to precipitate aluminum resinate and silica, and to neutralize free alkali and calcium compounds.

8.. A waterproof paper consisting of paper stock impregnated with a waterproofin material comprising finely divided ca cium -soap and an aluminum resinate binder fix ing such. soap on the fibers.

9. A waterproof paper, non-stickywhen wet, consisting of aper stock impregnated with a' water roo ng material comprising finely 1 divide calcium soap and a nonsticky binder.

10. A waterproof paper consisting of paper stock impregnated with a waterproof- 2. A process of producing waterproof paper, which comprises first mixing a solu signature. v

In'testimony whereof I have afiixed my ALBERTL. CLAPPI 7 

